1. Field of the Invention
The invention relates to a prosthetic foot with a forefoot spring, a heel spring and a base spring, the latter being connected to the heel spring and to the forefoot spring.
2. Background Description
U.S. Pat. No. 6,719,807 B2 describes a prosthetic foot with a two-dimensional resilient forefoot part, a two-dimensional resilient heel part, and a substantially rigid carrier part. One end of each of the forefoot part and heel part is connected to the carrier part, and the forefoot part and the heel part each work independently of the respective other part. The forefoot part extends forwards and substantially unidirectionally from its connection to the carrier part, while the heel part extends rearwards and substantially unidirectionally from its connection to the carrier part.
U.S. Pat. No. 5,181,933 describes a prosthetic foot with a securing means for facilitating the operation of engaging the foot with the stump of a prosthetic foot user. A large number of curved, energy-storing foot areas are secured on the securing means and extend downwards in order to rest on the ground. Each of the curved portions has an ankle area, the foot areas interact independently of each other with the ground, and the curved portions having a similar shape. A heel spring is secured in a releasable manner on a forefoot portion and extends rearwards. A similar construction is described in U.S. Pat. No. 5,514,185.
U.S. Pat. No. 5,776,025 describes a prosthetic foot with a securing area on which a downwardly extending, curved and partially slit spring is secured. A continuous spring with a heel area and a forefoot area is secured on the front lower end area of the spring. The continuous spring has a curved shape. A similar construction is described in U.S. Pat. No. 6,071,313.
US 2005/0203640 A1 describes a prosthetic foot with a resilient ankle area. Starting from an attachment adapter, an upper securing portion of the forefoot area extends obliquely rearwards and downwards and, after a curve, merges into a forwardly and downwardly extending arch portion, which ends in a toe portion. A heel spring extends in parallel as far as the ankle area, and, after the curve, a first portion assumes a greater inclination than the arch portion. The first portion is followed by another curve, such that a heel portion extends obliquely downwards and rearwards. The heel spring is therefore S-shaped. A lower base spring is connected to the rear end of the heel spring and to the toe area, and a cushion can be arranged between the toe portion and the front part of the base spring.
GB 306,313 describes a prosthetic foot with a U-shaped frame for attachment to a below-knee shaft, on which a heel part is arranged which is likewise U-shaped and is arranged at a right angle to the frame. A front part corresponding, substantially to the contour of a natural foot is arranged on the heel part. The front part is mounted elastically via resilient rods.
U.S. Pat. No. 4,721,510 describes a prosthetic foot having a hollow elastomer cosmetic shell with a relatively large internal space. In the area of the insertion opening, the sole has a thickened area to which an anchor plate is secured. A reinforcement plate is arranged on the anchor plate, and a stiffening spring with a forefoot spring area and a heel spring area is secured on the reinforcement plate. Arranged above the spring is a wedge on which the springs bear in the event of overloading.
U.S. Pat. No. 4,822,363 describes a prosthetic foot with an elongate and curved spring which has a proximal securing branch and, adjoining the latter, a forwardly extending forefoot branch. Arranged on the securing branch, there is a heel spring, which is of a curved design, either approximately S-shaped or L-shaped. In an alternative embodiment, a heel spring is secured releasably in the forefoot area and extends rearwards with a slight curvature.
U.S. Pat. No. 2,475,372 describes a prosthetic foot with an upper area on which a below-knee shaft can be secured in an articulated manner. A metatarsal area is mounted in an articulated manner on a heel area. The metatarsal area is adjoined by a forefoot area that is articulated thereon. The forefoot area is mounted resiliently via a spring mechanism.
U.S. Pat. No. 5,258,039 describes a resilient prosthetic foot with a forefoot spring and a heel portion that are connected to each other by an elastomeric ankle element. The forefoot spring has a longitudinal slit. The heel spring has a C-shaped design. In an alternative embodiment, the prosthetic foot is designed in one piece.
U.S. Pat. No. 6,669,737 B2 describes a resilient foot insert for an artificial foot, comprising at least two springs which in a side view, in an unloaded state, enclose between them an approximately triangular space and form a roof area. A securing element is arranged in the roof area. Starting from the securing element, a heel portion extends rearwards and downwards in a concave curve, while a forefoot portion extends forwards and downwards in a similarly concave curve. A separate base spring is connected, in the heel area and in the toe area, to the heel portion and to the forefoot portion.
U.S. Pat. No. 6,099,572 describes a resiliently elastic foot insert with at least one leaf spring, which comprises at least two leaf spring elements which are coupled in parallel and are arranged next to each other. The leaf spring elements are connected to each other at both ends and, between the two end areas, have a clearance from each other. The connection is designed to be rigid in terms of torque in at least one of the two end areas.